Planarization Method for Media

ABSTRACT

A planarization process may planarize a media disk that has data trenches between data features and larger servo trenches between servo features. A filler material layer is deposited on the media disk and provides step coverage of the trenches. The filler material has data recesses over the data trenches and servo recesses over the servo trenches that must be removed to produce a planar media surface. A first planarization process is used to remove the data recesses and a second planarization process is used to remove the servo recesses.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a continuation of and claims priority of U.S.patent application Ser. No. 12/895,360, filed Sep. 30, 2010, the contentof which is hereby incorporated by reference in its entirety.

FIELD

This disclosure is related to a method for planarizing media.

BACKGROUND

Magnetic recording media may be used in disk drives. The surfaces of themedia may need to be very smooth for proper operation of the magnetictransducer head relative to the media. Patterned recording media may beplanarized to produce a smooth surface.

BRIEF DESCRIPTION OF THE DRAWINGS

According to an embodiment, FIG. 1 illustrates an enlarged view of aportion of a DTR media disk;

According to an embodiment, FIG. 2 illustrates a cross section of amedia having a patterned resist formed by a stamper;

According to an embodiment, FIG. 3 illustrates a cross section of amedia having a descummed patterned resist;

According to an embodiment, FIG. 4 illustrates a cross section of amedia having a magnetic layer with etched trenches;

According to an embodiment, FIG. 5 illustrates a cross section of amedia having trenches after the resist may be removed;

According to an embodiment, FIG. 6 illustrates a cross section of amedia with filler material deposited over the trenches;

According to an embodiment, FIG. 7 illustrates an ion beam etch (IBE) ofthe filler material on a media;

According to an embodiment, FIG. 8 illustrates a cross section of amedia with a first filler material partially planarized by the IBE;

According to an embodiment, FIG. 9 illustrates a cross section of amedia with a protective layer over a single filler material layer;

According to an embodiment, FIG. 10 illustrates a cross section of amedia after the deposition of a second filler material layer;

According to an embodiment, FIG. 11 illustrates an IBE of the secondfiller material on the media;

According to an embodiment, FIG. 12 illustrates a cross section of amedia with a second filler material partially planarized by the IBE;

According to an embodiment, FIG. 13 illustrates a cross section of mediawith a protective layer over a single filler material layer;

According to an embodiment, FIG. 14 illustrates a flowchart showing aplanarization process;

According to an embodiment, FIG. 15 illustrates a cross section of amagnetic DTR media with trenches in the upper surface;

According to an embodiment, FIG. 16 illustrates a cross section of mediawith a layer of filler material deposited on the upper surface;

According to an embodiment, FIG. 17 illustrates an IBE of the fillermaterial on the media;

According to an embodiment, FIG. 18 illustrates a cross section of amedia with a filler material partially planarized by the IBE;

According to an embodiment, FIG. 19 illustrates a cross section of amedia with resist material deposited over the filler material;

According to an embodiment, FIG. 20 illustrates a cross section of mediawith filler and resist material selectively etched;

According to an embodiment, FIG. 21 illustrates a cross section of mediawith the resist material removed;

According to an embodiment, FIG. 22 illustrates a cross section of mediawith a filler layer planarized;

According to an embodiment, FIG. 23 illustrates a cross section of mediawith a protective layer;

According to an embodiment, FIG. 24 illustrates an enlarged view of aportion of a BPM media disk;

According to an embodiment, FIG. 25 illustrates a cross section of amedia having a patterned resist formed by a stamper;

According to an embodiment, FIG. 26 illustrates a cross section of amedia having a descummed patterned resist;

According to an embodiment, FIG. 27 illustrates a cross section of amedia having etched trenches and a patterned resist layer;

According to an embodiment, FIG. 28 illustrates a cross section of amedia with trenches in the upper surface;

According to an embodiment, FIG. 29 illustrates a cross section of mediawith a layer of filler material deposited on the upper media surface;

According to an embodiment, FIG. 30 illustrates an IBE of the fillermaterial on the media;

According to an embodiment, FIG. 31 illustrates a cross section of apartially planarized media with resist material deposited over thefiller material;

According to an embodiment, FIG. 32 illustrates a cross section of amedia with resist material deposited over the filler material;

According to an embodiment, FIG. 33 illustrates a cross section of amedia with filler and resist material selectively etched;

According to an embodiment, FIG. 34 illustrates a cross section of amedia with the resist material removed;

According to an embodiment, FIG. 35 illustrates a cross section of mediawith a filler layer planarized; and

According to an embodiment, FIG. 36 illustrates a cross section of mediawith protective layer.

DETAILED DESCRIPTION

Disk drives include rotating recording media and a head that may recorddata to the media and may read data from the media. The head may beattached to an arm that may move the head across the radius of the disk.By rotating the disk and moving the arm across the disk, the head may bepositioned over any portion of the disk surface. The movement of thedisk under the head may cause air to flow under the head so the headflies over the spinning magnetic recording media. The head may fly in avery stable manner when the surface of the media may be smooth. However,if the media surface has any defects such as depressions and/orprotrusions, the flying head may become unstable which may result inread or write errors and potential damage if the head contacts therotating media. The media can store data magnetically or optically.

Magnetic media may be formed by depositing several layers of differentmaterials on a substrate. Because the material layers may be depositeduniformly across the media, it may be possible to produce a smoothsurface. In contrast, surface defects may be more likely to occur indiscrete track recording media (DTR media) or bit patterned media (BPM)because different areas of the media have different features and may beformed from different materials deposited in the same plane. Forexample, DTR media may include recesses or trenches formed in thesurface of the media and BPM may include hard magnetic islandssurrounded by non-magnetic filler material. Because the upper layers maynot be homogeneous, there may be more potential for surface variations.

In some DTR media embodiments, a layer of magnetic material may bedeposited on the media substrate and etched to form the servo and datatracks. Material may be deposited between the servo and data tracks sothe adjacent magnetic data tracks may be separated by data trenches andthe adjacent servo tracks may be separated by servo trenches. The dataand servo trenches may then be filled with a filler material such as adielectric or non-magnetic material. The filler material completelyfills the trenches and covers the top surface of the media. Due to thetrenches, the upper surface of the filler material on the media may notbe planar. If the upper surface is improperly planarized, the uppersurface of the media may have depressions and/or protrusions that mayreduce the flying stability of the magnetic read/record head as ittravels over these areas. Precise planarization of the patternedmagnetic media may reduce head modulation and may also oprimize theflyability of the head.

The planarization of the patterned media upper surface may beparticularly difficult when the features on the media are not uniform insize. For example, DTR media may have separate data and servo featureswith different dimensions, however, both the data and servo features mayinclude circular trenches formed in the media substrate. The datatrenches form the data recording areas on the media and may be uniformin size so the depth, width and aspect ratio (ratio of the depth towidth) of each data trench may be substantially the same. In contrast,the servo trenches may be substantially larger (wider trench bottomwidth dimensions) than the data features and may have a broad range offeature sizes. The servo trenches may have various depths, widths andaspect ratios. Since the topographical features may have different sizesover different areas of the media, the filling and planarization of thedifferent-size servo and data features pose technical challenges.

FIG. 1 illustrates an embodiment of a DTR media 200 with a portion shownin magnified detail. The magnetic material 202 may be arranged in datatracks 271 and servo tracks 272 that may be circular and extend aroundthe DTR media 200. The data tracks 271 may be located in data regions241 and the servo tracks 272 may be located in servo track regions 242of the DTR media 200. The data tracks 271 may be thinner and spacedcloser together than the servo tracks 272. The spaces between the datatracks 271 may be data trenches 215 and the spaces between the servotracks 272 may be servo trenches 211. The data trenches 215 and servotrenches 211 may be filled with a non-magnetic filler material. Theupper surface of the filler material may be planar with the data tracks271 and servo tracks 272 so that the upper surface of the DTR media 200may be smooth which allows the read/write head of a disk drive to fly ina steady state manner over the media.

FIG. 2 illustrates a cross section of a portion of a magnetic mediahaving a substrate 201 and a magnetic layer 202. The substrate 201 maybe made of glass, aluminum, silicon or other suitable materials. Thehard magnetic layer 202 may be made of a hard magnetic material that mayinclude: one or more elements selected from the group consisting of Co,Cr, Fe, Ta, Ni, Mo, Pt, W, Cr, Ru, Ti, Si, O, V, Nb, Ge, B, and Pd.

An imprint resist layer 204 may be formed over the magnetic layer 202.In an embodiment, the imprint resist layer 204 may be a thermoplasticpolymer such as siloxanes that may be spin coated onto the magneticlayer 202. A rigid or a flexible stamper 206 having a patterned surfacewith servo trench features 405 and data trench features 407 may bepressed into the imprint resist layer 204 to emboss the pre-determinedstamper pattern in the resist 204. The resist 204 may be cured by heator exposure to ultra violet (UV) light while the stamper 206 may be incontact with the resist 204. After the resist layer 204 has been cured,the stamper 206 may be removed, leaving the pattern of servo trenchfeatures 212 and data trench features 216 in the resist layer 204. In anembodiment, the DTM media may have a track density of about threehundred fifty thousand tracks per inch (350,000 kTPI). Thus, there maybe 350,000 data trenches per inch in a radial direction on the media.Each track may be circular and each track may extend around the mediasubstrate 201.

With reference to FIG. 3, a descumming process may be used to remove theresist material 204 from the bottom portions of the servo trenchfeatures 212 and data trench features 216 in the resist layer 204. Thedescumming may be performed by a plasma process that bombards the resistwith ions to remove the small amount of resist particles at the bottomsof the servo trench features 212 and data trench features 216. Forexample, an argon plasma may remove the residual resist through physicalimpact. Alternatively, an oxygen plasma may remove the residual resistthrough physical impact and a chemical reaction. In other embodiments,other suitable descumming processes may be used.

FIG. 3 shows an embodiment of the magnetic media after the residualresist material 204 has been removed from the bottom portions of theservo trench features 212 and data trench features 216. Once theresidual resist material 204 has been removed, the hard magnetic layer202 may be etched. In other embodiments, various other suitablelithography processes may be used to pattern the resist layer depositedon the substrate. For example, photolithography, electron beamlithography, x-ray or projection lithography or other patterningprocesses may be used to form a patterned photoresist layer 204 on thehard magnetic layer 202.

With reference to FIG. 4, an anisotropic etch process may be performedto etch the servo trenches 211 and data trenches 215 into the magneticlayer 202. The selective etching technique for use in a givenapplication may depend upon the particular combination of the hardmagnetic material 202 and the resist mask layer 204, and may, forexample, be selected from among wet chemical and dry etching techniques,the latter including reactive plasma, ion beam, or sputter etchingmethodologies. During the etch processing, the hard magnetic material202 may be selectively removed at a faster etch rate than the resistlayer 204.

FIG. 5 shows a cross section of an embodiment of a discrete track media(DTM) substrate 201 after the resist material has been removed. Theprocess used to remove the photoresist layer 202 may depend upon thetype of resist material being used. In an embodiment, the resist may beremoved by using a plasma ashing process such as an oxygen (O₂) reactiveion etching (RIE). In a RIE process, the media may be placed in a vacuumchamber and exposed to an oxygen plasma which may remove the resist 351from the hard magnetic material layer 202, but may not remove or damagethe magnetic material 202. In other embodiments, any other suitableresist material removal process may be used. Large servo trenches 211may be formed between the magnetic servo tracks 272 and smaller datatrenches 215 may be formed between the magnetic data tracks 271 on thesubstrate 201. The servo trenches 211 may have a width of about 100 nmor less while the data trenches 215 may have a width of about 30 nm orless.

With reference to FIG. 6, in order for the upper surface of the media tobe smooth and suitable for read/write head flyability in a disk drive,the servo trenches 211 and the data trenches 215 may be filled with afiller material (dielectric or non-magnetic). The deposition of thefiller material 203 may result in step coverage of the servo features272 and data features 271. The servo trenches 211 and data trenches 215may be completely filled with the filler material 203. Thedifferent-sized trenches 211, 215 may cause the upper surface of thefiller material 203 to have recesses 221 over the servo trenches 211 andrecesses 225 over the data trenches 215. After the filler material 203deposition, the depths of the recesses 230 over the data trenches 215may be substantially the same as the depths of the recesses 211 over theservo trenches 211. The thickness of the filler material 203 may beabout 30-40 nm and the depths of the recesses 230, 228 may be about10-20 nm deep.

With reference to FIGS. 7 and 8, in order to smooth the upper surface ofthe media, the filler material layer 203 may be planarized using a highangle ion beam etch (IBE) process such as ion milling. In an embodiment,a noble gas such as argon may be used for the ion beams 278. Beams ofargon ions 278 may be directed towards the substrate at an angle and thephysical impact of the ions removes material from the filler materiallayer 203 to planarize the upper surface. Because the ion beams may bedirected at an angle relative to the upper surface, the filler material203 at the bottom of the low aspect ratio recesses 225 over the datatrenches 215 may be protected from the ion beam. In contrast, the higheraspect ratio recesses 221 over the servo trenches 211 may be wider andless protected by the servo tracks 272. Because the recesses 221 overthe servo trenches 211 may be more exposed to the ion beam, theserecesses 221 may be etched during planarization. The angle of the ionbeams may be about 2 to 70 degrees, although higher and lower angles mayalso be suitable. After IBE, the depth 230 of the recesses 225 over thedata trenches 215 may be reduced while the recesses 221 over the servotrenches 211 may remain substantially the same.

In an example, the depths of the recesses 230, 228 before IBEplanarization may be about 12 nm deep. After IBE planarization, therecess depth 230 over the data trenches 215 may be less than about 10 nmwhile the recess depth 228 over the servo trenches 211 may remain about12 nm. In other embodiments other planarization processes may be used.For example, it may be possible to planarize the filler material usingother processes such as chemical mechanical polishing (CMP). However,these other planarizing methods may be too expensive and time consumingfor commercial magnetic media production.

With reference to FIG. 9, in an embodiment the magnetic media may becompleted after the first layer of filler material 203 has beendeposited and planarized. A protective carbon layer 266 may be depositedon the top surface of the filler material 203 that acts as a protectivecoating and prevents damage to the media in the event of physicalcontact with a disk drive head. However, the upper surface of the carbonlayer 266 may not be perfectly planar.

With reference to FIG. 10, in other embodiments, the smoothness of thefiller material 203 surface may be optimized by not depositing thecarbon layer and adding a second layer of filler material 233 over thefirst layer of filler material 203. The second layer of filler material233 may further reduce the size of the recesses 235 over the datatrenches 215 and recesses 331 over the servo trenches 211. In otherembodiments, the second layer of filler material 233 may be depositedover the first layer 203 without planarizing the first layer 203.

With reference to FIGS. 11 and 12, an IBE process may be used to smooththe second filler layer 233. The IBE process may use an argon ion beam278 described above with reference to FIG. 7 to remove more materialfrom the higher aspect ratio recesses 331 over the servo trenches 211than the lower aspect ratio trenches 235 over the data trenches. Afterthe second filler layer 233 has been deposited and planarized, the uppersurface may be smoother and the recesses 235, 331 may be smaller.

With reference to FIG. 13, a protective layer of carbon 277 may bedeposited over the planarized second filler layer 233. However,variations in the upper surface may still exist. In an embodiment, thetarget smoothness of the upper surface may be an (roughness measurementsystem) RMS<1 nm. Thus, even with the deposition and planarization ofthe second filler material 233, the surface of the DTR media 201 mayhave height variations that may destabilize the read/write head flyingover the media 201.

In order to optimize the planarization of the DTR media surface, aplanarization method may be performed that utilizes differentplanarization processing for the data trench areas of the media and theservo trench areas of the media. FIG. 14 illustrates a flow chart ofprocesses for a planarization method. At 603, a DTR media having datatrenches and servo trenches may be provided. As previously described,the servo trenches may be significantly wider and have a larger aspectratio than the data trenches. Per 605, a filler material may bedeposited on trenched media filling the servo trenches and the datatrenches. Because the filler material layer conforms to the topographyof the underlying substrate, the filler material layer may have recessesover the servo trenches and the data trenches. At 607, an ion beam etchmay be used to planarize the substrate and remove the low aspect ratiorecesses in the filler material layer over the data trenches, but theplanarization may not remove the recesses over the servo trenches.

At the start of the second planarization, targeting the larger recessesabove the servo trenches, at 609, a resist layer may be deposited overthe entire media surface filling the recesses in the filler materiallayer over the servo trenches. The resist layer may also be planarized.Because the resist layer may fill the servo trenches, the thickness ofthe resist layer may be greater over the recessed servo trenches. Theupper surface of the media may be selectively etched 611. The selectiveetch may uniformly remove the resist material from all exposed areas ofthe media. The thinner areas of resist may be completely removed and theresist may remain over the servo trenches. The etch may then remove theexposed filler material. The selective etch may be stopped when theupper surface of the filler material layer over the data trenches may beapproximately planar with the filler material over the servo trenches.At 613, the remaining resist material may be removed from the media. At645, a final planarization may be applied to the entire media to createa smooth and even upper media surface. Additional finish processing maybe performed on the media such as applying a protective coating beforethe media may be used in a disk drive.

The described processes may be divided into at least two distinctplanarizations. The first planarization 601 planarizes the fillermaterial over the smaller data features and a second planarization 602planarizes the filler material over the larger servo features. The firstdata trench planarization 601 includes the filler deposition process 605and the first planarization process 607 to reduce smaller features. Theservo trench planarization includes the resist coating 609, theselective etch 611 and the resist removal 613. A final planarizationprocess 603 may also be performed on the entire DTR media after thefirst planarization 601 and the second planarization 602 have beencompleted. Examples of the various processes that may be used in theplanarization process described below.

With reference to FIG. 15, the substrate 301 has been processed asdescribed above with reference to FIGS. 2-5 above to form data trenches315 between the magnetic material data tracks 371 and servo trenches 311between the magnetic material servo tracks 372. In an embodiment, thewidth of the data trench 315 may be about 30 nm and the width of theservo trench 311 may be about 100 nm. The depths of the trenches may beabout 15 nm deep. In other embodiments, the aspect ratio of the datatrenches 315 may be about 2-4 and the aspect ratio of the servo trenches311 may be about 2-20. The magnetic material used to form the datatracks 371 and the servo tracks 372 may be CoCrPt, FePt, or any othersuitable hard magnetic material. The magnetic direction of the magneticmaterial in the data tracks 371 and the servo tracks 372 may beperpendicular to the plane of the substrate 301.

With reference to FIG. 16, a layer of filler material 303 may bedeposited over the substrate 301 to fill the servo trenches 311 and thedata trenches 315. Because the filler material provides step coverage ofthe substrate 301 topography, the top surface of the filler material 303has small data recesses 325 above the data trenches 315 and larger servorecesses 321 over the servo trenches 311.

The filler material 303 may be selected from the group comprisingsilicon nitride (SiN_(x)), silicon dioxide (SiO₂), nickel-tantalum(NiTa) or other suitable filler materials, and mixtures thereof. Thefiller material 303 may be deposited on to the upper surface of thesubstrate. The filler material 303 deposition may be optimized for smallfeature gap filling and topography reduction. Suitable depositionprocesses may include: chemical vapor deposition (CVD), plasma enhancedchemical vapor deposition (PECVD), physical vapor deposition (PVD), andother suitable deposition methods, or according to subsequentlydeveloped deposition processes.

With reference to FIGS. 17 and 18, in the first planarization,corresponding to the data trench planarization 601 of flowchart of FIG.10, the filler material 303 may be planarized. In an embodiment, thefirst planarization of the filler layer may be performed using an IBEprocess using ion beams 278 of a noble gas such as argon as describedabove with reference to FIG. 7. Because the data recesses 325 have a lowaspect ratio, the angle of the ion beams 278 may remove the smaller datarecesses 325 over the data trenches 315. However, the larger servorecesses 321 over the servo trenches 311 may be etched during the IBEprocessing and may still exist after the planarization. The filling ofthe data trenches 315 with the filler material 303 and the planarizationof the smaller recesses 325 constitute the first portion of the process,according to an embodiment.

As shown in FIG. 19, after the planarization the data recesses in thefiller material 303 over the data trenches 315 have been removed, aliquid resist material 351 may be applied over the filler material 303.The resist material 351 fills the servo recesses 321 remaining over theservo trenches 311 and may also cover the rest of the filler materiallayer 303 over the data trenches 315. The resist 351 may then beplanarized by heated reflow or nano-imprint lithography. If a heatedreflow process may be used, the resist 351 may be heated above its glasstransition temperature and the upper surface may become planar. Theresist 351 may then be cooled below the glass transition temperaturewhich causes the resist 351 to harden.

In an embodiment, a nano-lithography planarization process may be used,a planar stamper surface may be pressed against the liquid resist 351and the resist 351 may then be cured while in contact with the planarsurface of a stamper. The curing may be performed by heating the resist351 or exposing the resist 351 to UV light or an electron beam whichcauses the resist 351 to harden while in contact with the planarsurface. The stamper may be then separated from the hardened resistlayer 351. Resist may be deposited or applied to the filler materiallayer surface by spin-coating. Suitable resist materials that may beused may include: (1) UV-curable resist, liquid in form when applied andsubsequently hardened by UV or electron beam irradiation inducedcross-linking; and (2) thermal resist, softened by heating. See e.g., M.Colburn, I. Suey, B. J. Choi, M. Meiss, T. Bailey, S. V. Sreenivasan, J.G. Ekerdt and G. C. Wilson, J. Vac. Sci. Technol. B19, 2685 (20010; S.Chou, P. Krauss, and P. Renstom, Senience 272, 85 (1996). One example ofUV-cured resist may be Monomat available from Molecular Imprints, Inc.Another possible resist material may be spin on glass: SOG such as hydrosilsesquioxane (HSQ) which may be cured by exposure to an electron beam.In other embodiments, any other suitable resist material andplanarization process may be used.

A selective etch may be performed on the resist 351 and the underlyingfiller material 303. The “selectivity” of the etch refers to thedifferent etch rates for different materials. The etch may be highlyselective if the etch rate of the filler material 303 may be etchedfaster than the resist material 351. Because the resist 351 covers theentire media, the initial etch rate for the media may be uniform.However, after the underlying filler material 303 has been exposed, theetch rate of the filler material 303 may be higher than the etch rate ofthe resist 351. The resist 351 in the recesses 321 over the servotrenches 311 may protect the recesses 321 from being etched while theexposed filler material 303 that is not covered by the resist 351 may beetched.

With reference to FIG. 20, the DTR media is illustrated with theportions of the filler material layer 303 over the servo trenches 311protected from the selective etch by the resist 351 and all other areasof the filler material 303 etched away. The selective etching may removematerial from the upper surface of the filler layer 303 until the uppersurface is approximately planar with the upper surface filler material303 at the bottom of the recesses 321. The timing of the etch may bebased upon the predetermined etch rate of the filler material in nm/secand depth of the recesses 321 in nm. Thus, the duration of the etch maybe stopped at approximately time=depth of the recess/etch rate. It mayalso be possible to monitor the processing to determine the fillermaterial thickness. When the target filler material reaches the targetthickness, the etch processing may be stopped. The etch chemistry maydepend upon the filler material and resist being used. For example, ifthe filler material may be SiN and the resist may be Monomat, a fluorinebased RIE process may be used to etch the resist 351 and filler material303. In the RIE process, the media may be placed in a vacuum chamber andexposed to a fluorine based plasma which etches the resist 351 from thefiller material 303.

With reference to FIG. 21, after the selective etch may be completed,the remaining resist material 351 may be removed with an ashing processsuch as an oxygen (O₂) RIE. The media may be placed in a vacuum chamberand exposed to an oxygen plasma which etches the resist 351 but may notremove or damage the filler layer material 303. In other embodiments,any other suitable resist material removal process may be used. Theremoval of the resist 351 may complete a servo trench planarization ofthe process.

With reference to FIG. 22, in an embodiment an IBE milling process maybe performed to remove some of the filler material 303 over the magneticdata tracks 371 and the magnetic servo tracks 372. Thus, the uppersurface of the filler material layer 303 may be planar over with theupper surfaces of the data trenches 315 and the servo trenches 311. TheIBE milling may also planarize the upper surface of the media.

With reference to FIG. 23, a carbon layer 329 may also be deposited onthe top surface of the media 301 that acts as a protective coating andprevents damage to the media when there may be contact with a disk drivehead. The carbon layer 329 should have good adhesion to the fillermaterial 303 and the magnetic data tracks 371 and servo tracks 372 toprevent delamination. The carbon layer 329 may be further planarized tofurther optimize smoothness. In an embodiment, a target smoothness ofthe upper surface of the carbon layer 329 may be an RMS<1 nm.

The described planarization invention may also be applicable to bitpatterned media, BPM. With reference to FIG. 24, a portion of a BPM 300may be illustrated having data regions 441 made up of hard magneticmaterial data islands 471. Each island 471 may be a discrete datastorage bit. In an embodiment, the islands 471 may be arranged in aclose packed configuration. Therefore, the data trenches between theadjacent data islands 471 may be small and have small width/depth aspectratios. The BPM 300 also has servo regions 442 that have servo tracksthat may be made of servo islands 472 of a hard magnetic material. Theservo islands 472 may be larger than the data islands 471 and the servoislands 472 may be arranged in uniform rows and columns that may be lessdensely packed than the data islands 471. The servo trenches between theservo islands 472 may be larger than the data trenches and have a largerwidth/depth aspect ratio. The data trenches may have an aspect ratiomeasured between adjacent islands of about 1-2 and the servo trenchesmay have an aspect ratio of about 2-20 due to geometry variations. Thedata islands 471 and servo islands 472 have been simplified forillustrative purposes and may not be shown to scale. Like the DTR media,the servo trenches and the data trenches of the BPM 300 may also befilled with a non-magnetic filler material so the upper surface of theBPM 300 may be planar.

With reference to FIG. 25, a layer of a hard magnetic material 402 maybe deposited on a substrate 401 and a layer of imprint resist material404 may be deposited on the hard magnetic material 402. A rigid or aflexible stamper 406 having a patterned surface with servo trenchfeatures 405 and data recesses 407 may be pressed into the imprintresist layer 204 to emboss the pre-determined stamper pattern in theresist 404. The resist 404 may be cured by heat or exposure to ultraviolet (UV) light while the stamper 406 may be in contact with theresist 404. After the resist layer 404 may be cured the stamper 406 maybe removed, leaving the pattern of servo trench features 422 and datarecesses 426 in the resist layer 404. The processes used for patterningthe resist were described above with reference to FIG. 2.

With reference to FIG. 26, a descumming process may be used to removethe resist material 404 from the bottom portions of the servo trenchfeatures and data trench features in the resist layer 404. Thedescumming may be performed by a plasma process that bombards the resistwith ions to remove the small amount of resist particles at the bottomsof the servo trench features 412 and data trench features 416. Thedescumming processes were described above with reference to FIG. 3.

With reference to FIG. 27, after the residual resist material 404 may beremoved, the hard magnetic layer 402 may be etched to form the datatrenches 415 between the hard magnetic islands 471 and the servotrenches 411 between the hard magnetic servo tracks 472. With referenceto FIG. 28, the resist material 404 may be removed in an ashing processfrom the top surfaces of the hard magnetic islands 471 and the hardmagnetic servo tracks 472. With reference to FIG. 29, a layer of fillermaterial 404 may be deposited over the substrate 401, the magneticislands 471 and the magnetic servo tracks 472. The filler material 404may conform to the topography and provides step coverage of the magneticislands 471 and the magnetic servo tracks 472. The step coverage mayproduce data recesses 425 over the data trenches 415 and servo recesses421 over the servo trenches 411.

With reference to FIGS. 30 and 31, a data trench planarization may beperformed on the media using an IBE process. Ion beams 278 may bedirected at an angle at the upper surface of the media 401. The IBEprocess may remove material from the upper surfaces of the filler layer404 and the bottoms of the high aspect ratio servo trenches 421, but maynot remove material from the bottom of the low aspect ratio datarecesses 425 (shown in FIG. 29). Thus, the data recesses 425 may beremoved by etching the upper surface of the filler material 404. The IBEprocess may also planarized until the data recesses 425 have beenremoved.

With reference to FIG. 32, a resist layer 451 may be deposited on themedia over the filler material 404. The resist layer 451 may fill theservo recesses in the filler material 404. Details of the resist layerdeposition have been described with reference to FIG. 19 above. Withreference to FIG. 33, a selective etch may be performed on the media401. The resist layer 451 may be etched uniformly until the fillermaterial 404 may be exposed. The selective etch may then etch the fillermaterial 404 at a faster rate than the resist material 451. The exposedupper surface of the filler material 404 may be etched until the uppersurface may be approximately level with the bottoms of the servorecesses 421. Details of the selective etch have been described abovewith reference to FIG. 15.

With reference to FIG. 34, an ashing process may be used to remove theresist material 451 over the servo trenches 411. Details of the ashingprocess have been described above with reference to FIG. 21. Withreference to FIG. 35, in an embodiment an IBE milling process may beperformed to remove some of the filler material 303 over the magneticdata islands 471 and the magnetic servo islands 472. Thus, the uppersurface of the filler material layer 303 may be planar over with theupper surfaces of the data islands 471 and the servo islands 472. TheIBE milling may also planarize the upper surface of the media. Withreference to FIG. 35, a protective carbon layer 429 may be formed on theupper surface to complete the magnetic media. These processes have beendescribed above with reference to FIG. 22.

The present disclosure, in various embodiments, includes components,methods, processes, systems and/or apparatus substantially as depictedand described herein, including various embodiments, subcombinations,and subsets thereof.

1-2. (canceled)
 3. A magnetic device comprising: adjacent first andsecond areas; a magnetic layer comprising: a first set of trenches inthe first area with each trench of the first set of trenches having afirst size; and a second set of trenches in the second area with eachtrench of the second set of trenches having a second size; at least onenon-magnetic layer disposed on the magnetic layer in the first area andin the second area; and means, in the at least one non-magnetic layer,for enabling different planarization processing of the at least onenon-magnetic layer in the first area and in the second area.
 4. Themagnetic device of claim 3 and wherein the means, in the at least onenon-magnetic layer, for enabling different planarization of the at leastone non-magnetic layer in the first area and in the second areacomprises a first set of features that corresponds to the first set oftrenches and a second set of features that corresponds to the second setof trenches.
 5. The magnetic device medium of claim 3 and whereinindividual ones of the first set of features are configured to receive adifferent level of exposure from an angled ion beam than individual onesof the second set of features.
 6. The magnetic device of claim 3 andwherein the means, in the at least one non-magnetic layer, for enablingdifferent planarization of the at least one non-magnetic layer in thefirst area and in the second area comprises a resist layer having afirst thickness in the first area and a second thickness in the secondarea.
 7. The magnetic device of claim 6 and wherein the first thicknessof the resist in the first area enables a first rate of etch processingin the first area and the second thickness of the resist in the secondarea enables a second rate of etch processing in the second area.
 8. Themagnetic device of claim 3 and wherein the at least one non-magneticlayer comprises a filler layer formed of a material comprising at leastone of silicon nitride (SiN_(x)), silicon dioxide (SiO₂),nickel-tantalum (NiTa).
 9. The magnetic device of claim 8 and whereinthe at least one non-magnetic layer further comprises a resist layerdisposed on the filler layer.
 10. The magnetic device of claim 3 andwherein the first set of trenches and the second set of trenchescomprise discrete track media trenches.
 11. The magnetic device of claim3 and wherein the first set of trenches and the second set of trenchescomprise bit patterned media trenches.
 12. A magnetic device comprising:data and servo areas; means for enabling different planarizationprocessing in the data area and the servo area.
 13. The magnetic deviceof claim 12 and wherein the data area comprises data tracks separated bydata trenches, and wherein the servo area comprises servo tracksseparated by servo trenches.
 14. The magnetic device of claim 13 andwherein the means for enabling different planarization processing in thedata area and the servo area comprises a filler layer, in the data areaand in the servo area, having a first set of features that correspondsto the data trenches and a second set of features that corresponds tothe servo trenches.
 15. The magnetic device of claim 14 and whereinindividual ones of the first set of features are configured to receive adifferent level of exposure from an angled ion beam than individual onesof the second set of features.
 16. The magnetic device of claim 14wherein the means for enabling different planarization processing in thedata area and the servo area further comprises a resist layer having afirst thickness in the data area and a second thickness in the servoarea.
 17. An apparatus comprising: adjacent first and second areas; amagnetic layer comprising: a first set of trenches in the first areawith each trench of the first set of trenches having a first size; and asecond set of trenches in the second area with each trench of the secondset of trenches having a second size; means, disposed on the magneticlayer in the first area and the second area, for enabling differentplanarization processing in the first area and in the second area. 18.The apparatus of claim 17 and wherein the first set of trenches and thesecond set of trenches comprise discrete track media trenches.
 19. Theapparatus of claim 17 and wherein the first set of trenches and thesecond set of trenches comprise bit patterned media trenches.
 20. Theapparatus of claim 17 and wherein the means, disposed on the magneticlayer in the first area and the second area, for enabling differentplanarization processing in the first area and in the second areacomprises a filler layer, in the first area and in the second area,having a first set of features that corresponds to the first set oftrenches and a second set of features that corresponds to the second setof trenches.
 21. The apparatus of claim 20 and wherein individual onesof the first set of features are configured to receive a different levelof exposure from an angled ion beam than individual ones of the secondset of features.
 22. The data storage medium of claim 20 and wherein themeans for enabling different planarization processing in the data areaand the servo area further comprises a resist layer having a firstthickness in the first area and a second thickness in the second area.